Showing papers in "Behaviour in 1967"

An Experiment On Spacing-Out as a Defence Against Predation

Abstract: The paper is concerned with the tracing of a selection pressure which would account for the fact (believed to be sufficiently well established) that individuals of many well-camouflaged species live further away from other individuals of their species than the distance from which even bird predators are able to detect them. Artificially camouflaged hens' eggs were laid out in plots of different densities. Wild Carrion Crows were attracted to each plot by a standard "sample egg" which, while painted in the same way as the other eggs on the uppermost half, was laid out in a more conspicuous way. In spite of the fact that the Crows spent more time searching in the "scattered" than in the "crowded" plots, the crowded eggs suffered a much higher mortality. It is concluded that even for individuals of a well-camouflaged species it must be of advantage to live further away from others than the Direct Detection Distance of their predators. However, the experiments do not show that a crowded population as a whole suffers higher predation than a scattered population; experiments to test this and other aspects of the problem are in progress. It is argued that the absolute values of the density dependent mortality scores of the experiments cannot be applied to natural populations, because their density will in most cases be determined by other ultimate factors as well.

Social Structure Among Vervet Monkeys (Cercopithecus Aethiops)

Abstract: The social structure of vervet monkeys (Cercopithecus aethiops) is described on the basis of a one year field study in the Masai-Amboseli Game Reserve of south-central Kenya, East Africa. The major findings and conclusions are as follows: 1. They lived in relatively stable and closed heterosexual groups, ranging in size from 7 to 53 with a mean of 24 individuals. The sex ratio in these groups was about 1 : 1. 2. Home ranges of the groups varied in size from 0.071 to 0.37 square miles. Group territories varied from 0.067 to 0.30 square miles. There was no obvious correlation between group size and home range or territory size. 3. Some groups intruded into foreign territories significantly more than expected by chance. 4. Certain territorial boundaries were extremely stable, whereas others oscillated back and forth over a distance as great as 240 yards. 5. Although the groups were relatively closed, enough intergroup transfers were seen to permit concluding that extensive inbreeding was avoided. 6. Dominance among vervet monkeys was expressed in terms of priority to spatial positions, food, and grooming relationships, and through aggressiveness in agonistic encounters. Intragroup dominance relations demonstrated a strong trend toward a determined and linear relationship. 7. Several correlates of dominance were found, including : role in the Red, White, and Blue Display; unassisted defense of the territory; and copulation. 8. Many coalitions associated with agonistic encounters were formed through preferences of the monkeys. 9. Recipients of coalitions were of two types: dominant antagonists or subordinant non-antagonists. 10. Some of the coalitions had a temporary effect on dyadic dominance relations, either neutralizing or reversing them. 11. Group progressions were led by certain individuals. Leadership of progressions seemed primarily related to age and secondarily to dominance. 12. Each group regularly divided into sleeping subgroups at sunset, rejoining after sunrise. These subgroups were not formed at random but were formed, at least partly, with reference to mother-infant, coalitionary, and dominance relations. Formation of sleeping subgroups probably facilitated the concealment of vervets from nocturnal predators. 13. Territoriality and dominance are discussed in the light of DAVIS' hypothesis and the relative importance of spatial parameters. 14. Vervet territoriality was characterized by all-purpose areas that were defended by all age-sex classes of heterosexual groups throughout the year (excepting infants). Territoriality of this nature is uncommon among mammals, examples being found only among Primates and Rodentia. 15. The adaptiveness of vervet social structure is discussed.

An experimental study of intragroup agonistic behavior in rhesus monkeys (Macaca mulatta).

Abstract: A balanced social group of 17 rhesus monkeys, wild-trapped in northern India, was established in a colony cage of 1000 square feet in Calcutta. Quantitative data were obtained on behavioral repertoire, activity patterns and social interactions. Experiments were conducted to study the effect of certain environmental and social variables on the expression and intensity of intragroup agonistic behavior. A 25% food reduction resulted in no change in agonistic interactions, whereas a 50% food reduction and starvation regime resulted in a significant decrease in agonistic behavior. Investigative behavior increased, but grooming, sexual behavior, play, and aggressive behavior decreased. The monkeys became lethargic. The behavior of the monkeys resembled human behavior in famine and experimental starvation. A significant increase in agonistic behavior occurred when the distribution of the food was restricted, but the amount of food remained normal. Highly significant increases in the frequency and intensity of agonistic behavior occurred with the introduction of new monkeys who were social strangers. These results agree well with those of BERNSTEIN et al. on rhesus and KAWAI on Japanese macaques. The age and/or sex class corresponding to that of the introduced monkeys was the one which initiated most of the threat and attack behavior. A significant increase in agonistic behavior also occurred with a space reduction from 1000 square feet to 500 square feet. In general, social changes (i.e., changes in group membership) had a far greater impact on levels of intragroup aggression than did environmental changes such as starvation and crowding.

Disturbances of Maternal Behavior in the Rat Following Lesions of the Cingulate Cortex

Abstract: Using retrieving and other tests, the maternal behavior of a series of albino rats was tested before and after operative procedures. All lesions were made electrolytically and were stereotaxically placed. Motor acts observed during the behavioral tests included retrieving pups, licking pups, adopting the nursing position over retrieved pups and nest forming activities. Results of the operative procedures indicate that sham operations and ablations of a narrow strip of neocortical tissue lateral to the cingulate cortex do not appreciably alter the normal behavior pattern or interfere with the adequacy of maternal care. Animals with lesions of the anterior and posterior cingulate cortex (resulting in retrograde degeneration in the anterior thalamic nuclei) showed a disruption of these motor patterns including a distinct qualitative change in behavior towards pups. Slow retrieving with frequent pauses for grooming or sniffing about the cage, licking of unretrieved pups and little inclination to nurse pups characterized the behavior of these animals during the retrieving tests. All motor patterns seen in the normal animal were expressed by these rats but often in an irregular and confused manner. Pups would be repeatedly brought into and carried out of the nest site or dropped randomly about the cage. The nursing position would be adopted over one or two pups, in or out of the nest site, while the other pups were ignored. Judging from the relatively short latency of responding to the pups and nesting material and by the excitement evident in their aberrant pup retrieving and nest forming behavior, there seemed to be little or no loss of maternal motivation. The pups and nesting material were adequate stimuli to initiate the various motor acts observed in control animals. This aberrant behavior improved over repeated tests and by the third or fourth postpartum day the confusion seen in the earlier tests was less evident and most behavioral scores were close to the normal range. However, when these animals were tested in a strange, brightly illuminated cage, a thorough disruption of maternal behavior again occurred. Pre- and postpartum injections of prolactin resulted in no improvement. Supplying the animal with a small box with a narrow opening (a nest site preferred by normal animals) was also without effect in reducing the disturbed maternal behavior pattern. Lesions limited to the anterior or posterior cingulate cortex resulted in an intermediate loss which quickly improved during subsequent testing. Loss in maternal behavior in animals with partial and full cingulate lesions were significantly correlated with the severity of retrograde degeneration in the anterior thalamic nuclei. Maternal behavior (pup retrieving) which was induced in castrated male rats by exposing them to 1-3 day old pups each day did not suffer from neocortical lesions, but was disrupted by cingulate cortical lesions. It was concluded that the cingulate cortex in the rat participates in the integration or organization of complex unlearned activities.

A Quantitative Description of the Behavior of Rats During Copulation

Abstract: In the normal sequence of events during copulation in laboratory rats, the distinctive ejaculatory thrust of the male is preceded by a series of mounts with and without vaginal intromission, and is followed by a period of copulatory inactivity prior to the next series of mounts and intromissions. In 1922, after a study of the development of the sexual behavior pattern of the rat, C. P. STONE concluded that in the course of the copulatory encounter, "both males and females devote the greater part of their time to the performance of activities that have no relation to the sexual act". Indeed, if one combines the data of BEACH & JORDAN (I956) as representative of typical copulatory frequency data with those of PIERCE & NUTTALL (I96I) as representative of typical intromission duration data, one finds that less than one per cent of a typical rat sex behavior test is spent in actual intromission. Yet, there has been little systematic study of the behavior which occurs in the remaining 99 per cent of the test session. Most work has been on the frequencies and temporal spacing of those mounts, intromissions, and ejaculations which constitute such a small, albeit most interesting, part of the total pattern of activity. The most complete study is that of STONE (I922) on the behavior of maturing rats. As STONE was primarily interested in changes in behavior as the rats matured, he had little to say about changes in behavior within test sessions. GRANT & MACKINTOSH (I963) gave a brief qualitative description of some mating postures of the rat. Occasional reference has been made to such patterns as ear-wiggling, back-kicking, and hopping in the female rat (cf. BEACH, I942; I943; 1956), yet without systematic study of the complete behavior pattern. Knowledge of the complete behavior

The Habituation and Recovery of Aggressive Display in Betta Splendens

Abstract: Five Betta splendens were exposed to a mirror for ten days. The mirror was then removed for a recovery period, replaced for 48 hours, removed for a second recovery period, and so on in such a manner that each fish was given recovery periods of 15 minutes, 6 hours, 24 hours, 48 hours and 4 days in an order counterbalanced across subj ects. In most subjects the threat display increased during the first few minutes of mirror exposure (Fig. I). It decreased rapidly during the first 24 hours and then more slowly to a level which was low but above zero (Fig. 2). The recovery data indicate gradual recovery over the first 1-2 days after removal of the mirror; further recovery was either non-existent or very slow, and no subject showed a full return to the initial level.

Preoptic Activation of Frog Mating Behavior

Abstract: The effects of preoptic lesions on mating calling and mate orientation were studied in Rana pipiens and several species of tree frogs (Hylidae). Mating calling was evoked by electrical stimulation of the preoptic area of Rana pipiens and Bufo americanus. A new chronic electrode holder is described. It is concluded that the region of the dorsal magnocellular preoptic nucleus is needed for mate orientation and that the region of the ventral magnocellular preoptic nucleus is needed for mating calling. It is suggested that these preoptic regions may act mainly as activators of more posterior "centers". Mating calling may have evolved through the origin of connections between pre-existing preoptic activators and a pre-existing release calling "center", rather than through the origin of a new mating calling "center".

Courtship Behaviour in the Lesser Black-Backed Gull, Larus Fuscus

Abstract: [Le comportement sexuel du Goeland brun Larus fuscus a quatre elements principaux: la ceremonie d'accueil, l'attrait au nid, le repas de la cour, et la copulation. Les changements des frequences de ces elements pendant la saison de la nidification sont presentes. La ceremonie d'accueil et l'attrait au nid ne changent guere. D'autre part, la frequence du repas de la cour s'accroit brusquement pendant la quinzaine avant la ponte. Cela de la copulation s'accroit aussi pendant cette quinzaine, mais son accroissement commence a 3-4 semaines avant la ponte. Les follicules ovariens s'accroissent en poids pendant les dix jours qui precedent la ponte. On raisonne que le repas de la cour donne a la femelle l'alimentation supplementaire pour nourrir cet accroissement. La frequence la plus haute de la copulation a lieu au temps quand on compte sur la fertilisation. Toutefois, les copulations si frequentes qu'on trouve avant de l'accroissement des follicules, ne peuvent pas avoir une telle fonction, parce qu'il n'y a rien a etre fertilise; il n'y a aucune possibilite de l'accumulation des spermes, parce que l'oviducte n'est pas encore developpe. On a ete constate que les femelles ont besoin de la stimulation apportee par la cour des males pour pouvoir commencer l'accroissement final des follicules ovariens. Donc, on raisonne que la copulation joue ce role avec ces goelands. Il y a des indications que la copulation d'un couple de goelands stimule des copulations entre les couples voisins. On raisonne qu'il y a ici un mecanisme pour la synchronisation de la ponte. Les chainons temporels entre les elements individuels de la cour sont decrits. Il y a une chaine de comportement qui va de la ceremonie d'accueil au repas de la cour, et puis a la copulation. Une discussion de l'ajustement du comportement sexuel pendant la saison de nidification est aussi presentee. on arrive a la conclusion que la photoperiodicite fait probablement commencer ce comportement; la temperature n'a point d'effet. Il semble que la stimulation des oeufs le fait terminer., Le comportement sexuel du Goeland brun Larus fuscus a quatre elements principaux: la ceremonie d'accueil, l'attrait au nid, le repas de la cour, et la copulation. Les changements des frequences de ces elements pendant la saison de la nidification sont presentes. La ceremonie d'accueil et l'attrait au nid ne changent guere. D'autre part, la frequence du repas de la cour s'accroit brusquement pendant la quinzaine avant la ponte. Cela de la copulation s'accroit aussi pendant cette quinzaine, mais son accroissement commence a 3-4 semaines avant la ponte. Les follicules ovariens s'accroissent en poids pendant les dix jours qui precedent la ponte. On raisonne que le repas de la cour donne a la femelle l'alimentation supplementaire pour nourrir cet accroissement. La frequence la plus haute de la copulation a lieu au temps quand on compte sur la fertilisation. Toutefois, les copulations si frequentes qu'on trouve avant de l'accroissement des follicules, ne peuvent pas avoir une telle fonction, parce qu'il n'y a rien a etre fertilise; il n'y a aucune possibilite de l'accumulation des spermes, parce que l'oviducte n'est pas encore developpe. On a ete constate que les femelles ont besoin de la stimulation apportee par la cour des males pour pouvoir commencer l'accroissement final des follicules ovariens. Donc, on raisonne que la copulation joue ce role avec ces goelands. Il y a des indications que la copulation d'un couple de goelands stimule des copulations entre les couples voisins. On raisonne qu'il y a ici un mecanisme pour la synchronisation de la ponte. Les chainons temporels entre les elements individuels de la cour sont decrits. Il y a une chaine de comportement qui va de la ceremonie d'accueil au repas de la cour, et puis a la copulation. Une discussion de l'ajustement du comportement sexuel pendant la saison de nidification est aussi presentee. on arrive a la conclusion que la photoperiodicite fait probablement commencer ce comportement; la temperature n'a point d'effet. Il semble que la stimulation des oeufs le fait terminer.]

The development of social structure in free-ranging rhesus monkeys.

Abstract: The development of a social structure within a new colony of free-ranging rhesus monkeys was studied during their first 44 months on two adjacent islands, La Cueva and Guayacan, off the arid southwestern coast of Puerto Rico near La Parguera. Two of the nine social bands that formed in the colony disintegrated, two were removed to be held in enclosures, and five remained free-ranging. The observations on the development of social bands indicated that: (1) females experienced less difficulty in forming stable social units than males, (2) bands typically developed from a basic group of adult females dominated by an adult male, (3) the basic group of adult females was the most stable portion of the band and determined the rank of the band relative to other bands, (4) the presence of a dominant adult male was essential for the survival of the band as a social unit and, (5) males that did not join bands either remained semi-solitary or formed all-male groups. Stabilization of the social structure within and between bands was a gradual process. Inter-band shifts did not decline in frequency until two years after the colony's founding and many males did not join heterosexual bands until two and one-half years after the colony was founded. Attempts to form bands by artificially holding monkeys together for a period of time before releasing them were of limited success. Of four such attempts, only portions of two released groups remained together to form free-ranging social bands. Comparison between these results and those on a more mature population of free-ranging monkeys at Cayo Santiago indicates that the absence of kinship ties in the new colony may have been the cause of the instability observed.

Singing Behaviour of Blue-Winged and Golden-Winged Warblers and Their Hybrids

Abstract: 1. Songs of 12 Blue-winged Warblers (Vermivora pinus), 7 Golden-winged Warblers (V. chrysoptera) and 5 obvious hybrids were studied in the field near Ithaca, New York, U.S.A. 2. The primary song of the two species is distinctive. Hybrids sing one or the other of the parents' songs. Two birds had "reversed" songs, one a Blue-winged Warbler with Golden-wing song, the other a Golden-winged Warbler with Blue-winged song. The secondary song, sung early in the season only by disturbed birds or later in the season by undisturbed birds as well, is similar in the two species and hybrids. 3. Golden-winged Warblers and hybrids with Golden-wing song vary the number of notes in their songs according to the context. Fewer notes are given after mating (especially near the female), and following encounters with other males. In most instances, the more intense the preceding encounter, the shorter the song. Blue-winged Warblers differ in that they do not change the song directly at mating. A hybrid with a Blue-winged song and a Golden-wing with Blue-wing song resembled Golden-wings more in that they shortened song immediately after mating. The only bird that lengthened his song after mating was a Blue-wing with Golden-wing song. Both species and hybrids gave secondary songs following encounters with males. Secondary songs were usually given following more intense encounters than shorter versions of the primary song. Secondary songs under undisturbed conditions later in the season were more common in the Blue-wing. Flight songs which consist of secondary songs were observed only in Blue-wings and certain hybrids. Variants of this secondary song occurred only in the Blue-wing. 4. The two species differed in the amount of song after mating. Blue-wings had an abrupt decrease at the time of mating, Golden-wings a more gradual one. However, Golden-wings ceased singing earlier than Blue-wings and were usually silent during the parental phase. Hybrids resembled more the parent species whose song they sang. 5. The sequential patterning of songs within bouts was studied in birds with Golden-wing songs. Songs beginning bouts had fewer notes than those ending bouts. Under undisturbed conditions, songs with the same number of notes tended to follow each other and there were only two types of songs per bout. However, when disturbed, there was more often skipping and more than two songs per bout. 7. A hybrid (character) index was constructed of plumage patterns of the two species and hybrids. Song form and singing behavior were also scored. Form of song was not directly associated with plumage but singing behavior was. Therefore, these motivational factors are probably directly genetically controlled. 8. Evidence is presented that singing is a relatively independent tendency. Birds with Golden-wing songs give the primary song when the singing tendency is strong. When the general singing tendency is weaker, either absolutely or relatively because of the influence of other tendencies, particularly escape, the song is shortened. Secondary song seems to occur when the escape tendency is even stronger and/or the singing tendency weaker. 9. The functions of the primary and secondary songs are different, secondary songs playing no role in mate selection. The Golden-wing has developed more complexity in the primary song, the Blue-wing in the secondary. 10. Those vocalizations termed "song" probably have diverse functions as well as motivations in different passerines as a consequence of different evolutionary histories.

Experimental Programming of Life Histories

Abstract: Four experimental variables-whether or not the mother had been handled during her infancy, the presence or absence of handling of the pup, whether the young were born and reared in a maternity cage or a free environment prior to weaning, and whether the young were reared in a laboratory cage or a free environment between weaning and 42 days of age-were combined in a 24 factorial design (N = 6 Purdue-Wistar rats per group). Starting at 220 days of age the groups were given an extensive battery of tests. Analyses of variance extablished that there were many significant treatment differences (i.e., main effects and interactions) among the dependent variables. These significant differences may be attributed to the four independent variables, and the contribution of genetic variance to the treatment differences may be considered to be of a negligible amount. Intercorrelations were then computed among all the dependent variables, using the group mean as the basic score (i.e., N = 16 for each correlation coefficient). The intercorrelation matrix was factor analyzed. Three clearly identifiable factors were extracted. They were: emotional reactivity, field exploration, and consumption-elimination. A fourth factor, which could not be readily identified, was most heavily weighted with two measures of avoidance learning. The results establish that significant "individual differences" can be created by experimental means independent of any contribution from genetic variance. These experimentally created individual differences are highly stable, persisting for a period of at least 233 days. The isolation of a factor of emotional reactivity supports DENENBERG'S (1964) position that one of the major effects of early experience is to modify emotionality. The finding that emotionality and exploration are two independent factors has several theoretical implications.

The Sense Organs Employed By Cockroaches in Mating Behavior

Abstract: In Nauphoeta cinerea, Leucophaea maderae, and Byrsotria fumigata, female sexual behavior (mounting and "feeding" on the male's terga) is released by a male sex pheromone. The antennae serve as distance receptors for the male odor. The female's ability to detect and respond to the male rapidly can be correlated with distribution of thin-walled chemoreceptive sensilla on certain segments of the antennae. The mounting and feeding response of N. cinerea females to extracts of males was similarly correlated with the distribution of antennal chemoreceptive sensilla. In females of N. cinerea and L. maderae sensilla on the terminal segments of the maxillary and labial palps are capable of detecting the male in the absence of antennae. In B. fumigata females the antennae alone appear capable of detecting the male. Pycnoscelus surinamensis is unique in that headless females can mate. This is explained by the fact that the females do not feed on the male's terga prior to copulation. After ablation of various sense organs, the behavior of males of N. cinerea, L. maderae, and B. fumigata, differs from that of the females in that it is impossible to eliminate mating. The antennae bear the receptors which provide information promoting a rapid response to females. However, the maxillary and labial palps, and the cerci (except in B. fumigata) also play a role; the importance of these organs is shown only by combined removal with the antennae. The difficulty in eliminating mating in males of N. cinerea and L. maderae may be partly due to the fact that release of male courtship is not dependent upon stimuli from the female; these males may be induced to court by contact with other males. However, this is rare in B. fumigata and other sense organs (e.g., on the mouthparts other than the palps) may possibly be stimulated by the female sex pheromone. In P. surinamensis, the olfactory response to female sex pheromone is clearly correlated with distribution of chemoreceptive sensilla on the male's antennae. However, after bilateral antennectomy. the maxillary palps are capable of detecting the female on contact.

Sex differences in the development of independence of infant monkeys.

Abstract: Numerous elements of the behavior of mother and infant monkeys caged in controlled environments were recorded during the first 15 weeks of the infants' lives. The data on these elements were analyzed for sex-related differences in mean occurrence and in developmental trends. Differences in mutual independence related to the sex of the infant began to emerge soon after birth. The male infants and mothers began life more dependent on each other, but within a few weeks showed a rapidly accelerating change to greater mutual independence. The mother played an active role in the instigation of the greater independence of a male by higher initial punishment, less retaining, less orientation to the infant and less carrying of the infant. There were no indications of sex differences in the infants' behavior to support the concept that differential development of independence is a function of the infants' instigation. However, males appeared to be responsive to their independence by becoming more interactive with the environment. They soon directed relatively less of their behavior towards their mothers.

Social Relationship of Dairy Cows in a Feed Lot

Abstract: Twenty-four Holstein cows, divided into two equal groups, were observed in a feed lot for five consecutive days, eight hours each day. Each group was observed for a second five-day period approximately one month later. Three observers recorded the social interactions of the cows in the lot. Size, milk production, ingestive and eliminative behavior, and acts of servitude were tabulated for each cow. Agonistic behavior was recorded in the following categories; contact, bunting, forceful, nonforceful, and pushing. From the 3,463 contests observed, dominance values were computed by a least-squares procedure for each of the five categories. A social order was established within groups, combining all observations in all categories. Estimates of repeatability for dominance value were .97 from day to day in the same week, and .95 from day to day in different weeks. Partial correlation coefficients calculated indicated the highest relationship observed was between dominance value and weight. There appeared to be no correlation between dominance value and milk production. The data indicated the existence of at least three social structures within an established herd of dairy cattle - a milking order, a leadership-followership pattern, and a dominance hierarchy. The dominance hierarchy appeared to remain stable over a period of time. If animals are given sufficient opportunity for social contact, one day's observations can determine this social order.

Hormonal Control of Aggressive Behavior in Japanese Quail

Abstract: 1. Thirty-four five-month old male Coturnix were divided into 17 pairs on the basis of matched body weights (mean difference within pairs = 2 grams). The members of each pair were separated except during daily five-minute pair encounters. 2. Two classes of response were measured during the encounters: "head-grabs" and "pecks". A bird was called dominant if he performed more head-grabs and pecks than his pair-mate during the last three of four preexperimental encounters. 3. After the first four encounters the 17 pairs were divided into four groups: castrate, in which the dominant birds underwent bilateral gonadectomy (five pairs); sham operate, in which the dominant birds underwent the surgical procedure of the castrate group except for testis removal (four pairs) ; TCP injected, in which the submissive birds were administered testosterone cyclopentypropionate on a regular schedule (four pairs) ; and saline injected, in which the submissive birds were administered saline on the same schedule (four pairs). Pairs were observed for 23 encounters subsequent to the first experimental manipulations. 4. Gonadectomy had a clear, rapid effect on the behavior measured. From the fourth postoperative encounter through the eleventh, the (originally dominant) castrated birds performed zero head-grabs and zero pecks. The behavior of the pair-mates increased sharply during this time. 5. From the eleventh through the twenty-third postoperative encounter the castrated birds were given four injections of TCP. Androgen injections led to the reestablishment of original dominance relations in all cases. 6. Sham operations produced a mild effect on the established dominance relations. The operated animals showed relatively slight decreases in head-grabs and pecks; some pair-mates showed increased peck frequencies. In contrast to the behavior of the castrates, zero responding by the sham operates was rare. 7. TCP injections produced large changes in the behavior of three out of four intact submissive birds, and a slight change in the fourth. Androgen increased the average number of headgrabs and pecks exhibited by the injected animals by a factor of more than four; the pair-mates showed substantially reduced rates of responding (encounters 6-9). Cessation of androgen treatment produced a reversion to original relations within nine encounters after the last injection. 8. Treatment with saline had no effect on the originally established dominance relations. 9. The level of aggressive activity could be manipulated by varying the level of circulating androgen. Analysis of the functional significance of the observed behavior was made difficult by the close similarity of response in these homosexual contacts to that observed during heterosexual contact.

The Agonistic Behaviour of Juvenile Blennius Pholis L. (Teleostei)

Abstract: The agonistic behaviour of juvenile Blennius pholis, L. was observed in tanks of 28 x 43 x 30 cm and 75 x 40 x 30 cm, the larger tanks thus having a floor area 2.5 times that of the smaller tanks. The smaller tanks contained two fish, the larger ones either two or five fish. Those containing five fish thus had a population density equivalent to the smaller tanks. Eight main elements of agonistic behaviour were observed. They were; advancing, threatening, charging, snapping, fleeing, chasing, retreating and submitting. It was found that charging, fleeing, and chasing were by far the most common elements performed. Charging, threatening and chasing were performed most frequently by dominant fish, fleeing and retreating by subordinate fish. Advancing was performed more or less equally by both dominant and subordinate fish. It is suggested that submission is a displacement activity. Size difference was the main factor deciding dominance and the intensity of aggression, but the onset of light, food, available space, and the activity of the fish concerned were also of importance. The size of the tank and the number of fish it contained had an effect upon the relationship between size difference and the intensity of aggression. In the smaller tanks the intensity of aggression was directly related to the difference in size between the two fish. This relationship was not as clear in the larger tanks. Territoriality in the normally accepted sense of the word was not observed, because the fish were not seen to defend any particular area of the tank against others. A hypothesis suggesting the existence of 'individual distances' is put forward, in which the fish are considered to defend a particular area of space around themselves. These individual distances fluctuate in size according to the state of the aggressive drive of the individual and the amount of space available to it for movement. An attempt is made to relate the behaviour observed in the laboratory to that occurring in nature.

Interindividual associations in dogs.

Abstract: Interindividual behavior in a group of dogs reared together in a large field was studied to determine whether social and sexual interactions were more frequent in some pairs than in others. The experimental setting was designed to maximize the display of individual sympathies and antipathies. The basic test provided a situation in which behavioral interactions between a pair of animals was contingent on one animal approaching the other. One subject was restricted by a tether to a circular area with a diameter of approximately 12 feet while the other subject, the roving animal, was released into the outdoor field for 5 minutes, the duration of each test. Measures of association and a description of behavior were made and then the roles of each subject were reversed. Test combinations consisted of paired females, paired males and heterosexual pairs. Females were observed before, during, and after they were in behavioral estrus. Members of the opposite sex were most attracted to each other when the females were in estrus. However, all females were not equally attracted to all males. Three of four females showed preferences for some males over others. A preferred male enjoyed several advantages over nonpreferred males : (a) he was most frequently sought and solicited by the estrous female and she spent more time with him, (b) he was permitted to mount the female earlier in her estrous period, more frequently per day and, on more days, and (c) he was rarely prevented from investigating or mounting the female by being growled or barked at or by being bitten. Nonpreferred males were consistently rejected in this manner. One of the 5 males was readily accepted by all females. Otherwise, males preferred by one female were not uniformly preferred by the rest of them. In one case, a male preferred by one female was most frequently rejected by another. One female was equally receptive to all males. The preferences and aversions revealed by these subjects were evident the first time the females came into estrus and in subsequent estrous periods, whether natural or induced by exogenous hormones. These results were interpreted as indicating that sexual receptivity in the bitch is not completely dependent on ovarian hormones. Interactions between females were infrequent and brief as compared to those between two males or heterosexual pairs containing an estrous female. Strong individual associations between female pairs were not evident. Male-male interactions commonly involved elements of ritualized aggression while female-female interactions did not. The response of one male to another depended in part on which one had previously retreated in an aggressive encounter with the other. The submissive male in these stereotyped encounters was frequently visited, but he himself, rarely approached others. Some males preferred the company of some males to others. Members of a pair sympathetic to each other made frequent contacts of long duration and showed no aggression to each other.

The Maturation and Regulation of Glancing Off the Parents By Young Orange Chromides (Etroplus Maculatus: Pisces - Cichlidae)

Abstract: I During the parental period (3 to 4 weeks) young Etroplus maculatus skim or bounce against the body wall of the parent, a response termed glancing 2 The glancing rate for the individual does not change during the first week of free-swimming but thereafter it increases; the increase, however, is only apparent in fry that have been fed The glancing rate for the school decreases during the first week but this is due to mortality 3 The individual glancing rate is independent of the number of individuals within a school (25-125 individuals) regardless of age 4 Hour-to-hour changes in glancing rate also occur and are related to the time of feeding 5 The orientation of glancing when characterized by 3 divisions, a ventral, a medial, and a dorso-anterior division, remains unchanged during development 6 The orientation of glancing, when characterized by an anterior and a posterior division, shows definite ontogenetic changes The anterio-posterior changes in orientation are reinacted each day, but steadily less so as the fry become older 7 Feeding does not change the glancing rate for individuals about 7 days old or less, but it increases the amount of glancing 16-fold for fry 12 days old and 22-fold for fry 18 days old The hour-to-hour changes in glancing rate can also be predicted from pre-feeding performance 8 Feeding affects the school organization After feeding the school becomes more uniform, moves closer to the parent, and as it does the young glance more 9 Fry with normal parental care undergo progressive morphological changes Fry deprived of parental care have a high mortality rate, while growth and morphological differentiation are severely retarded After 9 days of parental care, fry have completed the major morphological changes and can survive independently of the parent 10 During the early free-swimming days of the fry, the number of mucus glands in the epidermis of the parent increases by 34% 11 When parents were coated with carbon powder it was shown that young actually eat from the parents' side when glancing, and presumedly eat mucus 12 The changes in behavior during development are discussed with regard to the possible mechanisms by which feeding influences glancing rate, causal factors that might affect orientation of glancing, and the possible functional and ecological significance of this behavior

Preference for Light of Short Wavelengths in Hatchling Green Sea Turtles, Chelonia Mydas, Tested On Their Natural Nesting Beaches

Abstract: Hatchling green sea turtles, Chelonia mydas, preferred blue and green stimuli to red when tested in a two choice situation on their natural nesting beaches. These stimuli when used singly were also more effective than the red in distracting turtles on their way to the sea. The preference for blues and greens over red was not simply dependent on overall intensity differences between the stimuli. There were in fact two components in the reactions of the turtles to light. There was a tendency to go to lights the more intense they were. Combined with this there was a tendency to go to lights of shorter wavelengths. Since turtles, if left unrestricted in these experimental situations, would rapidly reach the sea, the experiments were likely to have been testing some aspect of sea finding ability. HOOKER'S (1911) views on the importance of photic behaviour in sea finding are therefore generally confirmed, but whether the turtle prefers lights of short wavelengths because of their colour or because they appear brighter cannot yet be said. The relevance of these behavioural results to visual mechanisms in turtles is discussed, in particular the possibility of some shift in spectral sensitivity at a peripheral level in scotopic conditions.

Imprinting in Birds and Primates

Abstract: Birds and Primates might be expected to have some similar behaviour patterns because they have some similarities in the nature and organization of their distance and contact receptors. An analysis of the reactions of newly-hatched chicks and neonatal monkeys to objects reveals many similarities and suggests that the contact provided by objects is an important factor influencing these reactions. Further similarities are evident in the behaviour of neonatal chicks and monkeys which are reared without objects either alone or in small groups, and in the behaviour of these infants when they are subsequently presented with objects or placed in small groups. The behaviour of neonates towards large objects is analysed into approach responses mediated by distance receptor systems and contacting responses mediated by contact receptor systems. It is suggested that contact reinforcement is required for the establishment of enduring social attachments and for distance perceptions to become secondary reinforcers for social behaviour. Available data on the role of contact reinforcement in imprinting are reviewed. The fear behaviour of chicks and infant monkeys is compared. There are similarities in their fear responses to strange obj ects both when tested alone and when tested in the presence of imprinting objects to which they have developed social attachments. In both chicks and monkeys fear of the unfamiliar object or situation is alleviated by the presence of the imprinting object. The social and sexual behaviour of chickens and monkeys that have been reared in isolation is briefly described and the similarities of their abnormal and inadequate responses are indicated. Normal social and sexual behaviour is prevented by fear, aggression, and lack of acquired stimulus-response adjustments to an active social partner. A similar analysis of social attachment in the human infant is presented and it is suggested that contact stimulation is necessary for such attachment but not for the establishment of distance perceptions of a familiar environment. The smiling response is treated as an ambivalent fear/relief response involving recognition of familiar distance stimulation. Social smiling differentiates from this ambivalent response through reinforcement by the social partner. The paper is based on available published experimental studies of neonatal birds and Primates and is intended to provoke new analysis and further studies rather than to provide a definitive analysis of the behaviour of neonates.

The feeding behaviour of domestic chicks as a function of rate of pecking by a surrogate companion.

Abstract: The feeding behaviour of chicks was observed in the presence of a model hen that was made to peck at rates of 30, 60, 120, and 240 per min. under two conditions of presentation: with the beak striking the floor to make a tapping sound and with the beak failing to strike the floor for silent pecking. Tapping sounds were also presented at the four rates while the model remained notionless. Under the silent pecking conditions, the number of food pecks emitted by the subjects was found to increase with the rate of pecking by the model. The addition of the tapping sound enhanced this effect, particularly at the two higher rates. The tapping sounds alone had no apparent effect upon the feeding behaviour of the chicks. It was concluded that the pecking movements of companions can be important in controlling the feeding behaviour of chicks. The tapping sound was tentatively interpreted as a general motivator.

A study of problem solving by gibbons.

Abstract: Four gibbons were presented with five types of string-pulling problems based on those used by KOHLER to demonstrate insight. Contrary to the results of previous research on problem-solving ability in gibbons, all of the problems were solved quickly and efficiently. Their success is attributed to the fact that, in the present research, the strings were elevated so as not to be lying on a flat surface. Such a design is more suitable to the anatomy and sensory capacities of these animals and more in accord with the types of manipulable objects which are found in their natural environment. At least one of the problem types was solved insightfully. It is concluded that the sudden appearance of a complete, adaptive ("correct"), complex response sequence following a period of non-problem-directed responding which in turn follows a period of non-adaptive ("incorrect") attempts at problem solution objectively characterize the qualitatively unique learning process known as insight. It is suggested that objective identification of qualitatively unique learning processes is a prerequisite to the meaningful analysis of tool-using behavior.

Self-perception and species recognition in birds.

Abstract: If birds reared in isolation learn visual features of their own bodies, they could generalize from such learned perceptions and choose to associate with members of their own species rather than with other species when subsequently placed with other animals This self-perception hypothesis could account for some published studies showing preferential choice of own species by birds reared in isolation A series of experiments was conducted to test this hypothesis Typically, newly-hatched chicks were dyed red, or green, or were left their natural yellow colour After being reared for 8 days in visual isolation or in small social groups, the chicks were tested in a three-choice test apparatus for their approach to red, green, and yellow chicks A chick was scored for a choice if it reached a goal-box and tried to push through the separating wire-mesh In Experiment I, red and green chicks, reared socially or in isolation, were tested for their choice of red, green, and empty goals The socially-reared chicks clearly chose goal chicks of their own colour The isolate-reared chicks responded in an indiscriminate manner In Experiment 2, chicks of the natural yellow colour were used along with red and green ones Again, social-chicks chose goals of their own body colour, while isolate chicks responded indiscriminately Some generalization appeared to occur in the social-chick responses, particularly between green and yellow, with green and yellow chicks clearly avoiding the red goal To a lesser extent, red was generalized to yellow, so that red chicks avoided the green rather than the yellow goals In Experiment 3, newly-hatched yellow chicks responded to red, green, and yellow goals indiscriminately, showing that they have no innate companion-colour preference However, 8-day isolate-reared yellow chicks behaved like 8-day social-chicks and avoided red goals in favour of green and yellow ones Experiment 4 tested an hypothesis that isolate-chicks learn their own colour from their reflection in their drinking water Green and yellow chicks, reared in isolation for 8 days with no drinking water (which was administered by pipette directly into the crop, either in light or in darkness), failed to show any tendency to choose green and yellow goals preferentially to red and empty goals In Experiment 5, chicks coloured red, yellow or green were reared in mixed groups; one chick of one colour with two companions of another colour In this way chicks experienced companions either of one, or of two, colours The tests at 8-days showed that when two colours had been experienced either colour may be chosen, but that green was more often chosen than might have been expected It appeared that green was most, and red least, readily learned and responded to The 'natural' yellow colour tended to be confused with green Experiment 6 tested for the possibility of individual recognition in 8-day social-chicks by using cage-mates in one of the goals Responding was indiscriminate in yellow chicks tested in this way with yellow goal chicks Taken together, these experiments show that newly-hatched chicks have no preference for red, yellow, or green chicks, but that they learn the colour of their companions and selectively approach them by 8-days of age These results are compared with the published work on colour and approach and following responses in chicks In general there seems to be more evidence against colour preferences in such responses in newly-hatched chicks The apparent stronger preference shown by chicks that have experienced colours at the extremes of the visible spectrum could be due to the greater possibilities for generalization in birds trained to colours in the middle of the spectrum In any event, there seems no doubt that the colour of the companion is learned The self-perception hypothesis was not supported by the results of Experiments I and 2 However, if the colour groups are combined in Experiment 2, the isolate-chicks appear to have chosen their own body-colour significantly more than would be expected by chance Furthermore, in Experiment 3 yellow isolate-chicks clearly avoided red goals It appears, then, that isolates can develop a weak tendency to choose colours not too different from their own body-colour Experiment 4 showed that such a tendency did not develop if the chicks were not able to see their own reflection It must be concluded, therefore, that the self-perception hypothesis is tenable at least if perception through reflection in water is included It is not known whether, in the absence of reflected self-images, such a tendency would develop over a longer period of time through the bird seeing its own body directly This conclusion is discussed in relation with published studies of species and familial recognition in birds reared in isolation or in the company of other breeds or species

Coital Behavior in Dogs Iii. Effects of Early Isolation On Mating in Males

Abstract: Three groups of male beagles were reared from weaning to sexual maturity under special circumstances and their responses to estrous females were compared in a series of mating tests. Five dogs were reared under conditions of semi-isolation (SI). They lived in individual cages and had very little physical contact with other animals throughout the experiment. The 5 males constituting the control group also inhabited individual cages but for 15 min. each day they were set free in the colony room where they could interact with other uncaged dogs. A final group of 5 males was reared together with 5 females in a I-acre field. None of the subjects had contact with estrous bitches except during the mating tests. The copulatory performance of the control and the group-reared males was essentially the same, but that of the semi-isolates was deficient in one particular. SI males mounted estrous females as readily and as frequently as members of the other 2 groups, but the orientation of mounting was abnormal. Ninety-seven per cent of the mounts by control and group-reared males were oriented to the female's rear, whereas 39 per cent of the mounts by SI dogs were directed to the head, side, or flank of the receptive bitch. One consequence of this difference was that SI males achieved intromission in only 24 per cent of their tests, as compared with 58 per cent and 54 per cent for the control and group-reared animals.

The Critical Period and the Interval Between Hatching and Exodus in Mallard Ducklings

Abstract: Studies were made of the interval between hatching and exodus in the mallard. 1. The difference in time between the hatching of the first and the last egg in one clutch varies from 3 to 8 hours. If two females have laid their eggs in the same nest, the difference can be up to 30 hours. 2. The age of the ducklings at the time of departure is very often more than 16 hours, which is mentioned as the upper limit of the critical period, during which the imprintability of mallard ducklings reaches its maximum. 3. Ducklings that are hatched in hole-nests are older at the time of exodus than are ducklings from the more usual mallard-nest situated on the ground. A factor contributing to this might be that the possibilities for visual and thus also for auditory imprinting are very limited in the first case and that the exodus from a hole-nest is an unconditioned response solely to auditory stimuli, in contrast to the departure from a nest on the ground, which is caused both by visual and auditory stimuli.

The Breeding Behaviour of Sabine's Gull, Xema Sabini

Abstract: [Sabine's Gull, Xema sabini is a morphologically aberrant gull, breeding in the Arctic. This paper describes its breeding behaviour, as recorded in the region of Hooper Bay, W. Alaska (61° 35' N, 166° 05' W) in the summer of 1960. The object of this study has been, not just to describe the behaviour, but to try to relate it to the species' ecology, and also, by comparisons with other gulls, to clarify the taxonomic position of Sabine's Gull. Much of Sabine's Gull behaviour is similar to that of other gulls, but there are some aberrancies which occur either rarely or not at all in other species. Chief among these are the Quarter Upright, the emphasis on Hunched, as opposed to Upright, postures, the attraction of unmated females by Arch-and-Bow rather than Long Call, the direct feeding (as opposed to regurgitation) of the female early in the season, the rarity of Head Tossing in courtship feeding and copulation, and the throwback and Crouch in the Long Call postures. Evidently, Sabine's Gull is behaviourally as well as morphologically aberrant. It seems to be most closely related to such species as Franklin's Gull, Larus pipixcan. Contrary to MOYNIHAN'S (1959) suggestion, based on morphological criteria, there is no evidence of any relationship with the Swallowtailed Gull, Creagrus furcatus. The functions of the grey and black hood are discussed. It is also suggested that some of Sabine's Gull's morphological and behavioural peculiarities may be related to its breeding in small, loose groups rather than in dense colonies, on the flat tundra, and during the short Arctic summer. A partial analysis of the motivation of the agonistic and sexual behaviour was also made. The relations of the various agonistic postures to the tendencies to flee and attack are discussed. It is also concluded that the different postures adopted during the loud-calling phase of the Long Call depend on the position of the opponent and not on any motivational differences. The sexual behaviour seems to consist of two relatively independent systems - the Meeting Ceremony and "Luring". The interrelationships of the different patterns in "Luring" are analysed in more detail., Sabine's Gull, Xema sabini is a morphologically aberrant gull, breeding in the Arctic. This paper describes its breeding behaviour, as recorded in the region of Hooper Bay, W. Alaska (61° 35' N, 166° 05' W) in the summer of 1960. The object of this study has been, not just to describe the behaviour, but to try to relate it to the species' ecology, and also, by comparisons with other gulls, to clarify the taxonomic position of Sabine's Gull. Much of Sabine's Gull behaviour is similar to that of other gulls, but there are some aberrancies which occur either rarely or not at all in other species. Chief among these are the Quarter Upright, the emphasis on Hunched, as opposed to Upright, postures, the attraction of unmated females by Arch-and-Bow rather than Long Call, the direct feeding (as opposed to regurgitation) of the female early in the season, the rarity of Head Tossing in courtship feeding and copulation, and the throwback and Crouch in the Long Call postures. Evidently, Sabine's Gull is behaviourally as well as morphologically aberrant. It seems to be most closely related to such species as Franklin's Gull, Larus pipixcan. Contrary to MOYNIHAN'S (1959) suggestion, based on morphological criteria, there is no evidence of any relationship with the Swallowtailed Gull, Creagrus furcatus. The functions of the grey and black hood are discussed. It is also suggested that some of Sabine's Gull's morphological and behavioural peculiarities may be related to its breeding in small, loose groups rather than in dense colonies, on the flat tundra, and during the short Arctic summer. A partial analysis of the motivation of the agonistic and sexual behaviour was also made. The relations of the various agonistic postures to the tendencies to flee and attack are discussed. It is also concluded that the different postures adopted during the loud-calling phase of the Long Call depend on the position of the opponent and not on any motivational differences. The sexual behaviour seems to consist of two relatively independent systems - the Meeting Ceremony and "Luring". The interrelationships of the different patterns in "Luring" are analysed in more detail.]

The Control of Distress Vocalization By an Imprinted Stimulus

Abstract: Twenty two newly hatched ducklings (A. platyrhynchos) were either exposed to a moving imprinting stimulus under one of several experimental conditions or exposed to an empty stimulus compartment. During these procedures special equipment was used to record distress calls. Ss individually exposed to a moving stimulus emitted first more and then fewer distress calls than Ss individually exposed to an empty stimulus compartment. Ss individually exposed to the moving stimulus while in their cages emitted distress calls whenever the stimulus disappeared from the visual field, but not otherwise. Ss exposed to the moving stimulus while in the company of other Ss failed to emit distress calls during the imprinting procedures. In subsequent tests for the effects of the several procedures the imprinting stimulus was periodically presented and withdrawn. It was found that when tested in isolation: 1. Regardless of the conditions during imprinting procedures, Ss previously exposed to the moving stimulus emitted distress calls when the imprinted stimulus was withdrawn, but they seldom emitted distress calls when the stimulus was present. In general, Ss that had been exposed to the moving stimulus while in their cages (i.e., with subject movement restricted) as well as Ss that had been exposed to the stimulus in the company of other Ss displayed the same vocalization pattern as Ss that had been exposed to the stimulus in isolation. These findings indicated that neither freedom to move about nor social isolation during exposure to an imprinting stimulus are necessary conditions for the imprinting stimulus to acquire control over S's distress calls. 2. Ss previously exposed to an empty stimulus compartment emitted more distress calls in the presence of the imprinted stimulus than in its absence. This implied that prior exposure to an imprinting stimulus was a necessary condition for stimulus withdrawal subsequently to evoke distress calls. 3. Additional tests were concerned with the factors that played a role in the behavioral control exhibited by the imprinted stimulus. For example, in the previous tests during stimulus withdrawal the imprinted stimulus was stationary and hence silent. In Test 3, during periods of stimulus withdrawal the stimulus continued to move under conditions in which S could hear but not see it. As in the initial tests, Ss emitted many distress calls during stimulus withdrawal, but they emitted very few calls during stimulus presentation. This finding suggested that distress vocalization was primarily under the control of visual rather than auditory stimulation. Test 4 examined the effects of stimulus presentation and withdrawal when Ss were in their own cages versus out of them during testing. More distress calls were emitted when S's cages were removed than when Ss were tested while in their cages. This finding suggested that in part, the control over vocalization exerted by the imprinted stimulus was mediated by the familiarity of the stimulus configuration that prevailed at a given time. Test 5 examined the effects of stimulus presentation and withdrawal when S was tested in isolation versus in the company of a second duckling. Withdrawal of the imprinted stimulus yielded many distress calls when S was alone, but not when S was accompanied by a second duckling. This finding suggested that in isolated Ss the high incidence of distress calls in the absence of the imprinted stimulus was a reflectieon of the withdrawal of social stimulation.

A Behavioural Study of the Home-Cage Activity of the White Rat

Abstract: Traditionally, the activity of the white rat has been investigated with a variety of mechanical recording devices (activity-wheels, stabilimeters, photo-electric relay systems, etc.), but quite limited data are available on rat behavior per se. The purpose of the present study was to develop an observational time-sampling technique that would provide a comprehensive description and catalogue of the various activities exhibited by individual animals and to use this to investigate the home-cage activity of the male laboratory rat under normal and experimental conditions. The following were studied: (1) age-related changes in normal animals at three age levels (approximately 30, 60, and 100 days) ; (2) effects of food- and water-deprivation in young (age 30 days) and adult (age 100 days) animals; (3) effects of food- and water-deprivation in adult animals (age 100 days) which had previously experienced similar deprivation at ages 30 and 60 days. Home-cage activity was measured simultaneously along a large number of different behavioural dimensions, hence an increase or decrease in "activity" typically reflected changes in a number of categories. The main age-related changes in home-cage activity were a sharpening of the diurnal activity cycle and a decrease in vigorous ambulatory behaviour. The effects of the various deprivation conditions proved to be quite different. At both 30 and 60 days, food-deprived animals showed much greater activity in a number of categories than did water-deprived and control animals. Water-deprived animals were somewhat more active than controls, but maintained an alert, immobile position more than the other two groups. At 100 days of age animals undergoing their third food deprivation showed marked increases in activity and some of these effects persisted during post-deprivation, whereas animals undergoing their third water deprivation showed relatively small increases in activity. Animals food-deprived for the first time at 100 days showed fewer activity changes; but 100 day old animals water-deprived for the first time presented a mixed picture, being more active than controls in the afternoon but less active at night. It was concluded that the drive properties of hunger and thirst have distinct, different, and cumulative effects on the home-cage activity of the white rat.

An Analysis of Sexual Isolation in the Domestic Fowl: Ii. the Basis of Homogamy in Females

Abstract: (I) An experimental analysis of the mechanisms underlying homogamy in the domestic hen was made, because of the role of this trait in effecting potential sexual isolation between breeds and strains of chicken. (2) The principal stimuli and sensory modalities involved in breed and strain 'identification' were analysed by means of modification and comparative techniques. (3) It was demonstrated that the entire dimorphic plumage colour pattern of the Brown Leghorn cock is an important stimulus in 'identification' by females of that breed. However, females also discriminate between identically-coloured strains, implicating the involvement of other cues in the identification process. (4) Breed and strain specificity in male body size, courtship vocalisations, and non-vocal courtship patterns may have some isolating value, but is not of paramount importance in breed and strain 'identification' by hens. Specificity in other behavioural aspects of the phenotype (e.g. posture, deportment, activity level) was not examined, but should not be overlooked. (5) Homogamy appears to have a partly genetic basis in the Brown Leghorn hen, but specific (i.e. own-strain, heterosexual) prior experience is a necessary pre-requisite to the significant expression of the tendency under present conditions. (6) Heterosexual experience with strange-breed males enhanced sexual responsiveness to such and own-strain males; own-strain, heterosexual experience probably additionally enhanced stimulus specificity. (7) Wliilst no evidence suggesting that any brief, sharply-delineated, sensitive period for homogamy-enhancing experience existed in present material was forthcoming, it was demonstrated (a) that heterosexual experience prior to eleven weeks of age was not sufficient per se to effect a significant expression of homogamy subsequently and (b) that own-strain, heterosexual experience acquired after sexual maturity was efficacious as an enhancer of homogamy. (8) Differences in levels of solicitation behaviour and degree of homogamy exhibited between female groups deprived of own-strain, heterosexual experience for varying lengths of the juvenile phase are tentatively explained in terms of physical maturation and the ontogeny of social and sexual behaviour.

The Sun Compass of Fowler's Toad, Bufo Woodhousei Fowleri

Abstract: [Apparatus and techniques were developed to test bufonid's use of celestial cues to find preferred directions in controlled experiments. Toads were trained to select an escape direction relative to a sun lamp and were found to maintain a course at the same angle to the light cue when the apparatus was rotated, the light moved, when tested outdoors under the sun, and if various lamps (e.g., bright incandescent, dim incandescent, infrared, and red flood) were substituted for the sun lamp. Reference objects, learned muscular movements, sounds, and odors were eliminated as possible orientational cues in this investigation. Toads could not orient to the learned direction when the light cue was obscured and the shadows were evenly distributed. B. w. f owleri possess a clocking mechanism and are able to compensate for the apparent 15° per hour movement of the cue throughout a diel cycle. The azimuth of the cue seems to be more important than the altitude to toads. Trained animals can be diverted from a trained direction by conspecific calls after injections of sex hormones. Celestial orientation is considered a basic orientational mechanism and apparently functions in conjunction with other mechanisms in the natural environment of toads., Apparatus and techniques were developed to test bufonid's use of celestial cues to find preferred directions in controlled experiments. Toads were trained to select an escape direction relative to a sun lamp and were found to maintain a course at the same angle to the light cue when the apparatus was rotated, the light moved, when tested outdoors under the sun, and if various lamps (e.g., bright incandescent, dim incandescent, infrared, and red flood) were substituted for the sun lamp. Reference objects, learned muscular movements, sounds, and odors were eliminated as possible orientational cues in this investigation. Toads could not orient to the learned direction when the light cue was obscured and the shadows were evenly distributed. B. w. f owleri possess a clocking mechanism and are able to compensate for the apparent 15° per hour movement of the cue throughout a diel cycle. The azimuth of the cue seems to be more important than the altitude to toads. Trained animals can be diverted from a trained direction by conspecific calls after injections of sex hormones. Celestial orientation is considered a basic orientational mechanism and apparently functions in conjunction with other mechanisms in the natural environment of toads.]